The present invention relates to a disk drive apparatus including a motor, and to a motor which can be used in a disk drive apparatus.
In recent years, a motor which electrically alters current paths by a plural transistors has been widely used as a drive motor in an office automation equipment and an audio-visual equipment. A disk drive apparatus such as an optical disk drive apparatus (DVD, CD, and the like) and a magnetic disk drive apparatus (HDD, FDD, and the like) includes such a motor.
FIG. 29 shows a prior art motor, which alters current paths to the windings by PNP-type bipolar power transistors and NPN-type bipolar power transistors. The operation of the prior art motor is described hereinbelow. A rotor 2011 has a field part formed by a permanent magnet. In a position detector 2041, three position detecting elements (three position sensors) detect magnetic field of the field part of the rotor 2011. The position detector 2041 produces two sets of three-phase voltage signals Kp1, Kp2, Kp3, and Kp4, Kp5, Kp6 on the basis of the three-phase output signals of the three position detecting elements in response to the rotation of the rotor 2011.
A first distributor 2042 produces three-phase lower-side signals Mp1, Mp2, and Mp3 in response to the voltage signals Kp1, Kp2, and Kp3, thereby controlling the activation of lower-side NPN-type bipolar power transistors 2021, 2022, and 2023.
A second distributor 2043 produces three-phase upper-side signals Mp4, Mp5, and Mp6 in response to the voltage signals Kp4, Kp5, and Kp6, thereby controlling the activation of upper-side PNP-type bipolar power transistors 2025, 2026, and 2027. Accordingly, three-phase drive voltage signals are provided to windings 2012, 2013, and 2014.
In this prior art configuration, the position detector 2041 comprises three position detecting elements for detecting the rotational position of the rotor 2011. This has caused the necessity of a substantial space for installing these position detecting elements and the complexity of the wiring, and hence an increase in the cost.
On the other hand, a motor without a position detecting element is disclosed in the specifications of the U.S. Pat. Nos. 5,130,620 and 5,473,232, and the motor detects back-electromotive forces of the windings so as to obtain a rotational position of the rotor. The motor without a position detecting element, however, can not detect correctly the rotational position at a low rotational speed of the motor, since the amplitudes of the back-electromotive forces become too small to detect at a low rotational speed of the motor. So, it is difficult to drive and control the motor at a low speed. In particular, in case that the rotational speed is controlled by using the pulse signal responding with the detected back-electromotive forces, a large fluctuation of the rotational speed of the motor occurs at a low speed because of inaccurate detection of the pulse signal.
A motor with a single position detecting element is disclosed in the specification of the U.S. Pat. No. 5,729,102. The motor estimates the rotational electrical angle from the output of the single position detecting element, and supplies sinusoidal currents to the windings on the basis of the estimated rotational electrical angle. But, in the configuration of the motor according to the U.S. Pat. No. 5,729,102, it is difficult to estimate the rotational electrical angle with a fine step resolution. In particular, the error in the estimated electrical angle becomes larger at a higher rotational speed. Accordingly, a precise rotation control of the motor has been difficult.
In addition, since a microprocessor is used in the calculation of the estimated electrical angle and the generation of the drive signal, an inexpensive microprocessor can not be sufficient in the processing performance at a high rotational speed. This has caused a difficulty in the high-speed operation of the motor.
In an optical disk drive apparatus for reproducing DVD-ROM, CD-ROM, and CD disks, a stable operation is required over a wide range of rotational speed from 10,000 rpm at high-speed reproduction to 200 rpm at CD reproduction. In a rewritable disk drive apparatus for recording an information signal to a high-density disk and/or reproducing an information signal from a high-density disk such as DVD-RAM/RW, CD-R/RW, and the like, a precise rotation of the disk is required. In a magnetic disk drive apparatus such as HDD and FDD, a stable and precise rotation of the disk is required.
It is therefore an object of the present invention to solve the above-mentioned problems, respectively and concurrently and provide a disk drive apparatus and/or a motor which has the configuration to overcome all or some or each of the above-mentioned problems.
The disk drive apparatus in accordance with the present invention comprises: head means for at least reproducing a signal from a disk or recording a signal on said disk; processing means for at least processing an output signal from said head means and outputting a reproduced signal, or processing a signal and outputting a recording signal into said head means; a rotor, having a field part which generates field fluxes, for driving said disk; Q-phase windings (Q is an integer of 3 or more); voltage supplying means, including two output terminals, for supplying a DC voltage; Q first power amplifying means, each of said Q first power amplifying means including a first power transistor for forming a current path between one output terminal side of said voltage supplying means and one of said Q-phase windings; Q second power amplifying means, each of said Q second power amplifying means including a second power transistor for forming a current path between the other output terminal side of said voltage supplying means and one of said Q-phase windings; position detecting means for producing a position signal which responds with a rotation of said rotor; and activation operation means for controlling active periods of said Q first power amplifying means and said Q second power amplifying means responding with said position signal of said position detecting means, each of said active periods being larger than the period of 360/Q electrical degrees; and that said activation operation means comprises: time measuring means for measuring a time interval T0 which responds with an interval of said position signal; first timing means for changing the state of a first state signal at an interval of a first adjust time T1 which responds with said time interval T0 and is less than T0/2, and setting said first state signal substantially to a first predetermined state responding with the measuring operation of said time measuring means; second timing means for changing the state of a second state signal at an interval of a second adjust time T2 which responds with said time interval T0 and is less than T1/2, and setting said second state signal substantially to a second predetermined state responding with a changing operation of said first state signal; and signal producing means for producing at least an activation control signal which responds with said first state signal and said second state signal, thereby controlling an active period of at least one power amplifying means among said Q first power amplifying means and said Q second power amplifying means responding with said at least an activation control signal; and said signal producing means includes: slope means for producing a slope signal which responds with said second state signal; and shaping means for producing said at least an activation control signal which responds with said slope signal and said first state signal, said at least an activation control signal varying substantially smoothly in at least one of rising and falling slopes responding with said slope signal.
In this configuration, the activation to the Q-phase windings can be accurately controlled in response to a single position signal. So, a disk drive apparatus with only one position detecting element is realized, and the disk drive apparatus alters current paths to the Q-phase windings by using an output signal of the only one position detecting element and drives stably the disk in a predetermined direction. The activation control signal has a rising slope, a flat top, and a falling slope.
At least one of the rising and falling slopes of the activation control signal changes substantially smoothly in response to the slope signal. Accordingly, the alteration of current paths to the Q-phase windings becomes smooth. This reduces the pulsation of the generated drive force, and a disk drive apparatus with a reduced disk vibration and a reduced acoustic noise is realized. The slope signal can be an analogous signal which has at least one of rising and falling slopes, or alternatively a digital signal composed of pulses whose average gives a slope.
Further, the first timing means changes the state of the first state signal at an interval of the first adjust time T1 (where T1 less than T0/2) which responds with the measurement result (the time interval T0) of the time measuring means, and the second timing means changes the state of the second state signal at an interval of the second adjust time T2 (where T2 less than T1/2) which responds with the measurement result (the time interval T0) of the time measuring means. Accordingly, before the time measuring means outputs the next measurement result, the first timing means changes the state of the first state signal by a predetermined number of states. Before the first timing means executes the next change of the first state signal, the second timing means changes the state of the second state signal by a predetermined number of states.
The signal producing means produces the slope signal which substantially has a slope in response to the second state signal, and produces the activation control signal in response to the first state signal and the slope signal. Accordingly, even if the disk speed is changed, the signal producing means produces the activation control signal which varies substantially smoothly in response to the slope signal. Thus, even in a disk drive apparatus whose disk speed is changed in response to the radial position of the head means, current paths to the Q-phase windings are always altered smoothly. This reduces the pulsation of the generated drive force, and a disk drive apparatus with a reduced disk vibration and a reduced acoustic noise is realized.
Furthermore, the first timing means sets the first state signal to a first predetermined state in response to the measuring operation of the time measuring means. And the second timing means sets the second state signal to a second predetermined state in response to the changing operation of the first state signal. Accordingly, the slope signal is changed in synchronization with the changing operation of the first state signal. Thus, the activation control signal is accurately produced in synchronization with the rotation of the rotor, thereby avoiding a variation in the activation control of the Q-phase windings. In addition, in case that the disk rotational speed is controlled on the basis of the position signal, for example, the rotational speed is controlled stably and accurately even at a low speed. As a result, a high-performance disk drive apparatus with a reduced disk vibration and a reduced acoustic noise is realized by an inexpensive configuration having a simplified position detecting means.
The disk drive apparatus in accordance with another aspect of the invention comprises: head means for at least reproducing a signal from a disk or recording a signal on said disk; processing means for at least processing an output signal from said head means and outputting a reproduced signal, or processing a signal and outputting a recording signal into said head means; a rotor, having a field part which generates field fluxes, for driving said disk; Q-phase windings (Q is an integer of 3 or more); voltage supplying means, including two output terminals, for supplying a DC voltage; Q first power amplifying means, each of said Q first power amplifying means including a first power transistor for forming a current path between one output terminal side of said voltage supplying means and one of said Q-phase windings; Q second power amplifying means, each of said Q second power amplifying means including a second power transistor for forming a current path between the other output terminal side of said voltage supplying means and one of said Q-phase windings; position detecting means for producing a position signal which responds with a rotation of said rotor; and activation operation means for controlling active periods of said Q first power amplifying means and said Q second power amplifying means responding with said position signal of said position detecting means, each of said active periods being larger than the period of 360/Q electrical degrees; and that said activation operation means comprises: time measuring means for measuring a time interval T0 which responds with an interval of said position signal; first timing means for changing the state of a first state signal at an interval of a first adjust time T1 which responds with said time internal T0 and is less than T0/2; second timing means for changing the state of a second state signal at an interval of a second adjust time T2 which responds with said time interval T0 and is less than T1/2; and signal producing means for producing at least an activation control signal which responds with said first state signal and said second state signal, thereby controlling an active period of at least one power amplifying means among said Q first power amplifying means and said Q second power amplifying means responding with said at least an activation control signal.
In this configuration, the activation of the Q-phase windings can be accurately controlled in response to a single position signal. So, a disk drive apparatus with only one position detecting element is realized, and the disk drive apparatus alters current paths to the Q-phase windings by using an output signal of the only one position detecting element and drives stably the disk in a predetermined direction.
Further, the first timing means changes the state of the first state signal at an interval of the first adjust time T1 (where T1 less than T0/2) which responds with the measurement result (the time interval T0) of the time measuring means, and the second timing means changes the state of the second state signal at an interval of the second adjust time T2 (where T2 less than T1/2) which responds with the measurement result (the time interval T0) of the time measuring means. Accordingly, before the time measuring means outputs the next measurement result, the first timing means changes the state of the first state signal by a predetermined number of states.
Before the first timing means executes the next change of the first state signal, the second timing means changes the state of the second state signal by a predetermined number of states. Accordingly, since the alteration of current paths to the Q-phase is executed in response to the first state signal and the second state signal, the disk drive apparatus drives the disk stably and accurately.
For example, in case that a slope signal which substantially has at least one of rising and falling slopes is produced in response to the second state signal, the rising and falling slopes of the. activation control signal can be substantially smoothed in response to the slope signal. Then the alteration of current paths to the Q-phase windings is achieved smoothly. This reduces the pulsation in the generated drive force, and a disk drive apparatus with a reduced disk vibration and a reduced acoustic noise is realized.
Further, the number of the states of the first state signal in the time interval T0 and the number of the states of the second state signal in the first adjust time T1 remain constant even when the disk rotational speed has changed. So, the disk drive apparatus can produce such an excellent activation control signal that the alteration of current paths to the Q-phase windings is achieved smoothly in response to the activation control signal. Thus, even in a disk drive apparatus whose disk speed is changed in response to the radial position of the head means, current paths to the Q-phase windings are always altered smoothly. This reduces the pulsation of the generated drive force, and a disk drive apparatus with a reduced disk vibration and a reduced acoustic noise is realized.
The first timing means can set the first state signal to a first predetermined state in response to the measuring operation of the time measuring means, for example. And the second timing means can set the second state signal to a second predetermined state in response to the changing operation of the first state signal, for example. These easily achieve to synchronize the second state signal to the first state signal and to synchronize the first state signal to the position signal. Thus, the activation control signal is produced in synchronization with the rotation of the rotor, thereby avoiding a variation in the activation control of the Q-phase windings.
In addition, in case that the disk rotational speed is controlled on the basis of the position signal, for example, the rotational speed is controlled stably and accurately even at a low speed. As a result, a high-performance disk drive apparatus with a reduced disk vibration and a reduced acoustic noise is realized by an inexpensive configuration having a simplified position detecting means.
The motor in accordance with another aspect of the invention comprises: a rotor having a field part which generates field fluxes; Q-phase windings (Q is an integer of 3 or more); voltage supplying means, including two output terminals, for supplying a DC voltage; Q first power amplifying means, each of said Q first power amplifying means including a first power transistor for forming a current path between one output terminal side of said voltage supplying means and one of said Q-phase windings; Q second power amplifying means, each of said Q second power amplifying means including a second power transistor for forming a current path between the other output terminal side of said voltage supplying means and one of said Q-phase windings; position detecting means for producing a position signal which responds with a rotation of said rotor; and activation operation means for controlling active periods of said Q first power amplifying means and said Q second power amplifying means responding with said position signal of said position detecting means, each of said active periods being larger than the period of 360/Q electrical degrees; and that said activation operation means comprises: time measuring means for measuring a time interval T0 which responds with an interval of said position signal; first timing means for changing the state of a first state signal at an interval of a first adjust time T1 which responds with said time interval T0 and is less than T0/2, and setting said first state signal substantially to a first predetermined state responding with the measuring operation of said time measuring means; second timing means for changing the state of a second state signal at an interval of a second adjust time T2 which responds with said time interval T0 and is less than T1/2, and setting said second state signal substantially to a second predetermined state responding with a changing operation of said first state signal; and signal producing means for producing at least an activation control signal which responds with said first state signal and said second state signal, thereby controlling an active period of at least one power amplifying means among said Q first power amplifying means and said Q second power amplifying means responding with said at least an activation control signal; and said signal producing means includes: slope means for producing a slope signal which responds with said second state signal; and shaping means for producing said at least an activation control signal which responds with said slope signal and said first state signal, said at least an activation control signal varying substantially smoothly in at least one of rising and falling slopes responding with said slope signal.
In this configuration, the activation to the Q-phase windings can be accurately controlled in response to a single position signal. So, a motor with only one position detecting element is realized, and the motor alters current paths to the Q-phase windings by using an output signal of the only one position detecting element and drives stably the rotor in a predetermined direction.
The activation control signal has a rising slope, a flat top, and a falling slope. At least one of the rising and falling slopes of the activation control signal changes substantially smoothly in response to the slope signal. Accordingly, the alteration of current paths to the Q-phase windings becomes smooth. This reduces the pulsation of the generated drive force, and a motor with a reduced motor vibration and a reduced acoustic noise is realized.
The slope signal can be an analogous signal which has at least one of rising and falling slopes, or alternatively a digital signal composed of pulses whose average gives a slope. Further, the first timing means changes the state of the first state signal at an interval of the first adjust time T1 (where T1 less than T0/2) which responds with the measurement result (the time interval T0) of the time measuring means, and the second timing means changes the state of the second state signal at an interval of the second adjust time T2 (where T2 less than T1/2) which responds with the measurement result (the time interval T0) of the time measuring means.
Accordingly, before the time measuring means outputs the next measurement result, the first timing means changes the state of the first state signal by a predetermined number of states. Before the first timing means executes the next change of the first state signal, the second timing means changes the state of the second state signal by a predetermined number of states.
The signal producing means produces the slope signal which substantially has a slope in response to the second state signal, and produces the activation control signal in response to the first state signal and the slope signal. Accordingly, even if the motor speed is changed, the signal producing means produces the activation control signal which varies substantially smoothly in response to the slope signal.
Thus, even in a motor whose rotor speed is changed, current paths to the Q-phase windings are always altered smoothly. This reduces the pulsation of the generated drive force, and a motor with a reduced motor vibration and a reduced acoustic noise is realized.
Furthermore, the first timing means sets the first state signal to a first predetermined state in response to the measuring operation of the time measuring means. And the second timing means sets the second state signal to a second predetermined state in response to the changing operation of the first state signal. Accordingly, the slope signal is changed in synchronization with the changing operation of the first state signal. Thus, the activation control signal is accurately produced in synchronization with the rotation of the rotor, thereby avoiding a variation in the activation control of the Q-phase windings.
In addition, in case that the rotational speed is controlled on the basis of the position signal, for example, the rotational speed is controlled stably and accurately even at a low speed. As a result, a high-performance motor with a reduced motor vibration and a reduced acoustic noise is realized by an inexpensive configuration having a simplified position detecting means.
The motor in accordance with another aspect of the invention comprises: a rotor having a field part which generates field fluxes; Q-phase windings (Q is an integer of 3 or more); voltage supplying means, including two output terminals, for supplying a DC voltage; Q first power amplifying means, each of said Q first power amplifying means including a first power transistor for forming a current path between one output terminal side of said voltage supplying means and one of said Q-phase windings; Q second power amplifying means, each of said Q second power amplifying means including a second power transistor for forming a current path between the other output terminal side of said voltage supplying means and one of said Q-phase windings; position detecting means for producing a position signal which responds with a rotation of said rotor; and activation operation means for controlling active periods of said Q first power amplifying means and said Q second power amplifying means responding with said position signal of said position detecting means, each of said active periods being larger than the period of 360/Q electrical degrees; and that said activation operation means comprises: time measuring means for measuring a time interval T0 which responds with an interval of said position signal; first timing means for changing the state of a first state signal at an interval of a first adjust time T1 which responds with said time interval T0 and is less than T0/2; second timing means for changing the state of a second state signal at an interval of a second adjust time T2 which responds with said time interval T0 and is less than T1/2; and signal producing means for producing at least an activation control signal which responds with said first state signal and said second state signal, thereby controlling an active period of at least one power amplifying means among said Q first power amplifying means and said Q second power amplifying means responding with said at least an activation control signal.
In this configuration, the activation of the Q-phase windings can be accurately controlled in response to a single position signal. So, a motor with only one position detecting element is realized, and the motor alters current paths to the Q-phase windings by using an output signal of the only one position detecting element and drives stably the rotor in a predetermined direction. Further, the first timing means changes the state of the first state signal at an interval of the first adjust time T1 (where T1 less than T0/2) which responds with the measurement result (the time interval T0) of the time measuring means, and the second timing means changes the state of the second state signal at an interval of the second adjust time T2 (where T2 less than T1/2) which responds with the measurement result (the time interval T0) of the time measuring means. Accordingly, before the time measuring means outputs the next measurement result, the first timing means changes the state of the first state signal by a predetermined number of states.
Before the first timing means executes the next change of the first state signal, the second timing means changes the state of the second state signal by a predetermined number of states. Accordingly, since the alteration of current paths to the Q-phase is executed in response to the first state signal and the second state signal, the motor drives the rotor stably and accurately.
For example, in case that a slope signal which substantially has at least one of rising and falling slopes is produced in response to the second state signal, the rising and falling slopes of the activation control signal can be substantially smoothed in response to the slope signal. Then the alteration of current paths to the Q-phase windings is achieved smoothly. This reduces the pulsation in the generated drive force, and a motor with a reduced motor vibration and a reduced acoustic noise is realized. Further, the number of the states of the first state signal in the time interval T0 and the number of the states of the second state signal in the first adjust time T1 remain constant even when the rotational speed has changed. So, the motor can produce such an excellent activation control signal that the alteration of current paths to the Q-phase windings is achieved smoothly in response to the activation control signal. Thus, even in a motor whose rotor speed is changed, current paths to the Q-phase windings are always altered smoothly. This reduces the pulsation of the generated drive force, and a motor with a reduced motor vibration and a reduced acoustic noise is realized.
The first timing means can set the first state signal to a first predetermined state in response to the measuring operation of the time measuring means, for example. And the second timing means can set the second state signal to a second predetermined state in response to the changing operation of the first state signal, for example. These easily achieve to synchronize the second state signal to the first state signal and to synchronize the first state signal to the position signal. Thus, the activation control signal is produced in synchronization with the rotation of the rotor, thereby avoiding a variation in the activation control of the Q-phase windings.
In addition, in case that the rotational speed is controlled on the basis of the position signal, for example, the rotational speed is controlled stably and accurately even at a low speed. As a result, a high-performance motor with a reduced motor vibration and a reduced acoustic noise is realized by an inexpensive configuration having a simplified position detecting means.
The above-mentioned and other configurations and their operations are described below in detail in the section of Brief Description of the Drawings.